Abstract: A programming system is provided in which a control program for an implantable medical device is constructed from program modules that are selected by a physician. Only the selected modules are loaded into the memory of the implantable medical device, each one of which provides the control functions necessary to provide a different therapy or diagnostic function. Because a physician typically does not need to elect all of the available therapies or diagnostic routines, the resulting control program may be smaller than a general purpose program designed to implement all of the possible treatments to a patient. Further, a greater selection of therapies and diagnostic routines may be provided, without necessitating an increase in the memory capacity of the implantable medical device.

Abstract: A system and method for safely altering the function of an implanted pacemaker in a noninvasive manner includes an implantable programmable pacemaker and a non-implantable programming device. The pacemaker includes a pulse generator that generates stimulation pulses as controlled by a control program. The control program, and associated control parameters, are stored in an implantable memory included within the pacemaker. The pacemaker further includes a telemetry circuit that allows the control parameters to be selectively changed or altered from a location remote from the pacemaker (i.e., a non-implanted location). The programmer includes a telemetry head for establishing a telemetry link with the pacemaker's telemetry circuit. Once a telemetry link is established, the programmer may be selectively operated to download a new control program into the pacemaker memory, thereby replacing the old control program previously stored in the pacemaker memory.

Abstract: An implantable medical system, having an implanted therapy-generating apparatus which administers a medical therapy in vivo to a treatment site remote from the therapy-generating apparatus, includes at least one optical conductor connected between the therapy-generating apparatus and the tissue at the treatment site, or an additional implantable medical device. Energy and/or information can be transmitted by optical signals using the optical conductor, in a safe and noise-free manner. Each location at which the optical signals are to be transmitted or received is provided with an optoelectrical converter, or an electro-optical converter, as appropriate.

Abstract: A pacing lead having a stylet introduced anti-inflammatory drug delivery element advanceable from the distal tip electrode. The element is preferably formed as a moldable biocompatible composite material. The element has a biocompatible matrix material which may be combined with drugs and therapeutic agents to deliver the drugs and agents by co-dissolution or diffusion to the point of either passive or active fixation. The drug delivery element may be rigid and serve to center the active fixation element, preferably a helix, for active fixation of the lead in the myocardium.

Abstract: A heart defibrillator includes a defibrillation circuit for delivering defibrillation pulses. The defibrillation circuit also emits a pre-pulse before the defibrillation pulse. The pre-pulse is not as intense as the defibrillation pulse, but is still intense enough to induce mechanical contraction of muscles in parts of the thorax and possibly the heart.

Abstract: The present invention includes a body implantable lead having a multipolar proximal connector, at least a first conductor coupled to at least one stimulating electrode, a sensor for sensing at least one physiologic parameter of the body, and a second and a third conductor coupled to the sensor. The sensor is hermetically sealed in a D-shaped housing. Sensor components are mounted onto a microelectronic substrate which is advantageously placed on an inner flat portion of the D-shaped housing. End caps having sealing rings, either glass frit or metal, are used to seal the ends of the shell. A hermetic seal is easily achieved by heating the sealing material until they re-flow between the end caps and the shell. Advantageously, the sensor terminals are sized to fit snugly within a narrow bore of the end cap which is then circumferentially welded closed. The D-shaped sensor is placed on a carrier having at least two lumens.

Abstract: An implantable defibrillator has a charging circuit which charges a capacitance, electrodes for delivering energy from the capacitance to a heart, and a switching stage for discharging the capacitance through the electrodes and across heart tissue to defibrillate the heart, as needed. A non-inductive current limiter is connected in vivo in the discharge path for limiting the current supplied to the heart tissue to predetermined maximum value.

Abstract: An implantable heart defibrillator and a method for defibrillating a heart, employ a shock pulse generator for delivering a defibrillation shock to a heart, the delivered energy being mechanical. The shock pulse generator includes an electromechanical energy converter which generates, e.g., pressure, by means of a piezoelement, in a pressure chamber. Pressure is transmitted by a fluid in an electrode devised like a hydraulic line to a balloon-like electrode head in contact with heart tissue. The generated pressure causes the electrode head to expand and deliver a mechanical shock to the heart corresponding to the pressure.

Abstract: A system for administering medical therapy includes an implantable medical apparatus containing an audio transmitter and an audio receiver for respectively transmitting and receiving extracorporeally audible audio signals. The system also includes an extracorporeal programming and control apparatus, which also includes an audio transmitter and an audio receiver. The medical apparatus can thus communicate directly, in both directions, with the extracorporeal programming and control apparatus by means of audio signals. Such communication can take place, for example, via a telephone line, so that the patient in whom the medical apparatus is implanted need not be physically present at the location of the extracorporeal programming and control apparatus in order to establish communication.

Abstract: A lead, for use in combination with an implanted pulse generator which may be a pacemaker or defibrillator or combination thereof. The lead can deliver an electrical charge to pace, cardiovert or defibrillate the heart, and can sense cardiac activity in the heart. The lead may include additional sensor electrodes capable of sensing electrical or physical activity in the atrial cavity. The lead allows cardioversion and/or defibrillation stimuli to be provided by a large surface area electrode which is passively implanted in the ventricle, to allow the pulse generator to provide appropriately synchronized atrial-ventricular pacing, cardioversion or defibrillation.

Abstract: A cardiac arrhythmia is terminated by stimulating the heart during the narrow "region of susceptibility" or termination window of the arrhythmia cycle based upon a statistically significant starting value. The present invention will store a plurality of successful critically timed intervals and compute a central value (e.g., average, mean, median, etc.) and a measure of variability (sample range, standard deviation, etc.). The measure of variability is used to determine the termination window size. In one embodiment, the present invention then "scans" symmetrically-centrifugally about the statistically significant starting value. In an alternate embodiment, the present invention employs ranked scanning, that is, scanning according to the frequency of occurrence of previously successful starting values. The number and size of steps could be either programmable, or automatically computed by the pulse generator based upon the termination window size.

Abstract: An implantable pacemaker continuously records pacing events and their respective rates of occurrence in sequence, as they occur, into an Event Record stored in a circular buffer. The circular buffer always contains the most recent events and rates collected. The recording of the pacing events selectively occurs at every event, or at sampling rates of one event per fixed sample interval. A programming device, coupled to the implantable pacemaker through a telemetry link, selectively retrieves the recorded pacing events and rates from the Event Record and reports subsets thereof in condensed or summarized form using numerical and/or graphical formats. The pacing event data collected in the Event Record is three-dimensional in that each pacing event includes a pacemaker event, an associated pacemaker or heart rate, and a real time interval. The programming device also calculates and reports statistical information from the data collected in the Event Record.

Abstract: An implantable heart defibrillator is equipped with at least one intracardiac defibrillation electrode. A post-therapy apparatus is arranged to emit, after a defibrillation pulse, at least one stimulation pulse through the defibrillation electrode, the stimulation pulse having energy far higher than the energy in a normal heart stimulation pulse for cardiac pacing, but less energy than a normal defibrillation pulse.

Abstract: An implantable cardioverter/defibrillator has an electrode system including two electrodes, at least one of the two electrodes being adapted for placement in a peripheral vein of the heart, the peripheral veins constituting the venous side of the coronary vessels running between the base of the heart and the apex of the heart.

Abstract: For detecting tachyarrhythmia of the heart, the partial pressure of gases physically dissolved in the blood is measured, preferably the partial oxygen pressure pO.sub.2, and a fast variation and/or a variation of the measured partial pressure pO.sub.2 that exceeds a prescribed degree is utilized as a criterion for the detection of a tachyarrhythmia. An apparatus for treating tachyarrhythmia of the heart operating according to the above method includes a sensor for identifying the partial pressure of gases dissolved in the blood, an evaluation unit supplied with the sensor output for recognizing rapid changes of the partial pressure or changes of the partial pressure that exceed a prescribed degree, the output of the evaluation unit being connected to circuitry for triggering the tachyarrhythmia treatment.

Abstract: An accelerometer-based, multi-axis physical activity sensor for use with a rate-responsive pacemaker, and a method for fabricating the sensor, are provided. The multi-axis physical activity sensor includes a cantilever beam having a film of a piezoelectric polymer adhered to each surface of an electrically conductive substrate. The piezoelectric films are highly resistant to fracturing during manufacture and in use, and they provide a strong output signal when stressed in response to bodily accelerations. A mass is mounted to a free end of the cantilever beam, and is substantially offset with respect to a planar surface of the beam so as to impart multi-axis sensitivity to the physical activity sensor. The accelerometer-based, multi-axis physical activity sensor provides an output signal that is communicated to pacemaker circuitry using a pair of electrical conductors.

Abstract: An external diagnostic/programming device is disclosed which includes means for both displaying intracardiac electrical signals sensed and telemetered from an implantable pacemaker in real-time, and for storing the intracardiac electrical signals for subsequent retrieval and analysis. The subsequent analysis selectively includes processing means for processing the signals off-line (i.e., not in real-time), using various signal processing strategies, such as digital filtering and frequency domain spectral analysis. The off-line signals may also be recursively processed in order to enhance the detection of a particular physiologic phenomena manifested by, but not readily discerned within, the unprocessed real-time signals.

Abstract: A rotatable pin, screw-in pacemaker lead assembly has a conductor coil enclosed within a silicone insulating tube. The conductor coil has a distal end secured to a helix electrode and a proximal end including a rotatable connector pin. The outer surface area of the conductor coil is coated with a super thin film of biocompatible Teflon. The Teflon coating substantially reduces the friction between the conductor coil and the inner wall of the insulating tube during lead fixation, thereby substantially reducing the number of turns of the connector pin required to effect fixation of the helix electrode.

Abstract: A suture sleeve for anchoring the lead body of an implantable medical device includes a tubular body having an exterior surface defining at least one annular, suture-receiving groove. The exterior surface further includes at least one longitudinally extending groove intersecting the at least one annular suture receiving groove and having ends extending longitudinally beyond the at least one suture receiving groove. The interior surface of the tubular body includes a plurality of inwardly extending projections having surfaces adapted to engage the lead body to prevent the sleeve from sliding along the lead body when the lead body is held vertically.The suture sleeve is fabricated of a biocompatible, polymeric material to which has been added color pigment and a radiologically dense material to render the suture sleeve readily visible to the naked eye against surrounding bodily tissue as well as radiologically visible.

Abstract: A programmable offset is added to an automatically generated baseline reference value to provide a Threshold value used by the rate-responsive sensor processing circuits of an implantable rate-responsive pacemaker to determine the significance of a sensor input signal. The rate-responsive pacemaker provides stimulation pulses on demand at a pacing rate determined by a sensed physiological parameter. The physiological parameter is sensed by a physiological sensor included within, or coupled to, the rate-responsive pacemaker. The physiological sensor generates a sensor input signal having a magnitude that varies as a function of the sensed physiological parameter. The invention provides a way for the rate-responsive pacemaker, when operating in an autothreshold mode, to automatically determine when the magnitude of the sensor input signal is sufficiently large to justify an increase in the pacing rate.